1. Field of the Invention
The present invention relates generally to methods and apparatus for exchanging heat with the body of a patient.
2. Description of the Related Art
It has been discovered that the medical outcome for a patient suffering from severe brain trauma or from ischemia caused by stroke or heart attack is improved if the patient is cooled below normal body temperature (37° C.). Furthermore, it is also accepted that for such patients, it is important to prevent hyperthermia (fever) even if it is decided not to induce hypothermia. Moreover, in certain applications such as post-CABG surgery, it might be desirable to rewarm a hypothermic patient.
As recognized by the present invention, the above-mentioned advantages in regulating temperature can be realized by cooling or heating the patient's entire body. Moreover, the present invention understands that since many patients already are intubated with central venous catheters for other clinically approved purposes anyway such as drug delivery and blood monitoring, providing a central venous catheter that can also cool or heat the blood requires no additional surgical procedures for those patients. However, single purpose heat exchange catheters such as are made by Innercool Therapies of San Diego, Calif. and Radiant Medical of Portola Valley, Calif. can also be less optimally used.
Regardless of the particular catheter used, it is clear that heat must be removed from or added to the coolant that flows through the catheter. As recognized herein, it is desirable that a heat exchange system for a heat exchange catheter consume minimal energy and space. Small size is desired because space is often at a premium in critical care units. Moreover, as also recognized herein, for patient comfort it is desirable that such a heat exchange system generate a minimum amount of noise. As still further understood by the present invention, it is desirable that the heat exchange system be easy to use by health care personnel, and provide for monitoring systems and convenient temperature control. U.S. Pat. No. 6,146,411, incorporated herein by reference, discloses one such heat exchange system. It is the object of the present invention to still further address one or more of the above-noted considerations.